Look no further, @Michaelak.

If you'll pay the invoice sent by your subcontractors in the middle or end of the month. You'll record this as a Bill. As per my colleague, @GlinetteC discussed above, Expense transactions are those paid at the time of purchase. On the other hand, Bill transactions are those purchases that you'll pay at a later date. 

Follow along below to create a Bill right away:

1. Click the +New button.
2. Choose Bill. 
3. Enter the name of your subcontractor in the Vendor field.
4. Input the Bill date (date you receive the invoice) and Due date (date you'll pay the invoice).
5. Fill in the column for Category or Item details. It depends on what type your business owes to the subcontractor.
6. Once done, hit Save.  

Then, to record payments on the bill you've created, please head to Enter bills and record bill payments page for the detailed instructions.

Also, QBO offers some reports to help you monitor your paid and unpaid bills. To get started, just go to the Reports menu and scroll down to the What you owe section. 

Let me know if you have further questions in recording transactions with your subcontractors. I'm always here to give answers and clarifications. Have a great day ahead.